| 摘要 |
PURPOSE:To achieve improvement of accuracy of controlling a recording position without complicating the structure of an encoder, by a method wherein a slit of a specified form through which a specified quantity of light passes is installed in a section to an origin of a recording position, and comprehensive sensitivity is controlled according to output of a photointerruptor when the slit is scanned. CONSTITUTION:A record is scanned with a photointerruptor provided under a carriage 21 and is closed-loop controlled by a positional detection signal with a linear encoder composed of a slit board 2. Further, slits 6 structured at an interval corresponding to recording resolution and slits 5 provided on a left side from a home position of a recording head 22 are formed to the slit board 2, and a transmission part and a dark part which have a same horizontal width are alternately arranged to the slits 5 to obtain average quantity of light when the slits 6 are scanned. Then, the photo-interruptor is composed of an LED1, a photo-transistor 4, and slits 3 for preventing disturbance light. Both emission light quantity and reception light quantity are controlled with a microprocessor, and comprehensive sensitivity is controlled over a broad range. |
